In a mobile crane, a rotary table of an upper structure is typically rotatably connected to a mobile crane undercarriage via a ball rotary connection or roller rotary connection. If the rotary connection is not exactly centered on the rotary table, a radial variance between the rotary connection and the rotary table can occur upon first assembly of the rotary connection to the rotary table. When a rotary position transducer is disposed on the rotary table of the upper structure, an undesired radial variation on engagement of the rotary position transducer with the circumferential ring gear of the rotary connection also occurs. In the prior art, therefore, one disposes the rotary position transducer at an end of a bendable arm, which is fixed to the rotary table of the upper structure with its other end and holds the rotary position transducer to the ring gear under preload. By the elastic deformation of the bendable arm, the radial variation is compensated for. Since the rotary connections have very large diameters, due to manufacturing tolerances, variations in the concentricity of the ring gear often also occur, which are also compensated for by the bendable arm.
However, upon rotating the upper structure, the bendable arm protruding beyond the rotary table and the rotary position transducer can easily be damaged. For example, a lifting means placed on the undercarriage, such as belts or chains, can get caught on the arm and bend it.
Thus, the invention is based on the object to provide a rotary position transducer assembly, which compensates for the occurring radial play on the rotary connection and avoids damages to the rotary position transducer at the same time.